Is there a Tree of life

Is there a tree of life? Most people have the impression that all the life on this planet originated from a single event. The idea being that all biology has DNA, so it all had to come from a single source. Other evidence for this idea comes from the fact that the difference between a human and say a reptile isn't all that much in terms of DNA. Small variations in the code make vast differences in species.

Certainly humans all have common ancestry; and we are obviously related to much of the life on the planet. So we can assume a tree of life of some sort. But there are a lot of questions as to how speciation works and how far back common ancestry goes.

It is assumed by most people that humans and primates had a common ancestor a few million years ago. But who is to say where we actually split?

There is an interesting fact that has recently been discovered. Life started on this planet very early on. As it happens, much earlier than anyone had thought. From what we now understand, life started on this planet less than a billion years after the earth was formed. The earth being 4.5 billion years old, we found bacteria that seems to have appeared as early as a billion years after the earth formed.

A bacteria is a complex system. For it to exist DNA has had to have time to develop. Cells have had to have time to form. So it seems that life formed as soon as the earth was solid or stable enough to sustain it.

But is DNA the beginning of life? Apparently not. Recent work by Sidney Altman, professor of Molecular Biology at Yale University has discovered that RNA can act like DNA even though it no longer does. This is because RNA can have “enzymatic function”. There is good evidence that suggests that the first life forms had single strand RNA instead of double strand DNA. It is being called: RNA world. Even now some viruses store all their genes in RNA and have no DNA at all.

Some scientists are even wondering if life could form without DNA or RNA, but with some other type of code or mechanism. This is being talked about at NASA. Scientists are even looking for other types of life right here on earth. For example, in a few inches of soil there might be millions of microbes. It came as a bit of a surprise to me that not nearly all have been studied extensively or even cataloged In the sea there are millions more we know nothing about. Seems that for obvious reasons we only pay attention to the ones that can harm us. They all look pretty much alike. Could there be life that did not come from our family tree right here in our own back yard?

There is no real concrete definition of life. Chris McKay, a scientist at NASA and Seti, is quoted as saying it doesn't matter that there is no good definition for life. “We will know it when we see it.” But will we? I did another essay on my own opinion of life so I won’t go into that in this one.

The interesting thing here is that if life began here very early on; really as soon as it could, basic life must be abundant out there. Recently we have found many new planets; some of which are probably very much like earth as far as size and position go. It would be very surprising to find no other life out there. But only time will tell whether life is special, or the default. I’d bet on it being inevitable.

Besides which, even here life springs up in places we never thought possible. There may be many life forms on planets where we couldn't survive. Perhaps even some in our solar system. It doesn't have to be intelligent life to prove the point. But again, we will have wait and see.

So there may not be one tree of life on this earth, or at least there may have been others that died out or even that co-exist with ours. In other words: life may not have been a single event on this planet at all. It may be that the formation of DNA/RNA is inevitable or the natural byproduct of the formation of certain types of planets and the electro-chemical interactions that take place just because they are there; as it were.

And though we know all of life on this planet is related, who is to say it all came from the same event and the same primordial sea or pool? We may have common ancestors with the primates, but it is also possible that those ancestors were not mammals or even reptiles. They may have been single celled animals. We may have developed parallel to them for millions of years rather than having split relatively recently. There is so much still to learn, and we have barely scratched the surface of it all.

Craig Venter and his institute have created the first artificial DNA and consequently a new species. Yes, he has almost created life from scratch, and soon will have. He is also the man responsible for sequencing the human genome. The only reason we can’t say he already has created life is because he used a bacterial cell to do it and replaced its DNA with his own code. Next he’ll have to build his own cell from scratch. I have little doubt he will do that in the very near future if he hasn't already.

These scientists like Venter and Altman are poised to change the world as we know it. What they have discovered so far has already altered the way we understand evolution. That is to say how it all happened.

It amazing to think that what makes us who and what we are comes down to acids, carbon sugars, phosphates, and four bases: thymine, cytosine, guanine, and adenine. That’s what our DNA is made of. The proteins that are manufactured by this code give us our traits and characteristics.

But so what if there is not one tree of life? Nothing really changes. In a sense all life is related because all life is made of molecules which in the end are all made of atoms; and they are the same all over the universe, as are the laws of physics which are responsible for how they all interact.

14 comments

"From what we now understand, life started on this planet less than a billion years after the earth was formed. "

Source, please? How was the life dated?

Sue Adams 5 years ago from Andalusia

"And though we know all of life on this planet is related, who is to say it all came from the same event and the same primordial sea or pool?"

I tend to go along with the idea that there was more than a single beginning. When the solidification of the planet occurred many of its parts must have contained the preliminary elements that later became life, surely.

Slarty O'Brian 5 years ago from Canada Author

nicomp

William Schopf found bacteria in rock in the 1990s that have been dated to 3.5 billion years. His discovery has been verified and validated several times. Read: The Cradle of Life, or Microfossils of the Early Archean Apex chert. He claimed they were an early type of cyanobacteria which still exist today. But there has been some controversy about that. So that means DNA had to develop earlier than that. But he was only the first to discover this. Since then many more people have discovered bacteria in rock dated to 3.5 billion years. It’s pretty much an accepted fact now.

Slarty O'Brian 5 years ago from Canada Author

I completely agree, Sue.

nicomp 5 years ago from Ohio, USA

"William Schopf found bacteria in rock in the 1990s that have been dated to 3.5 billion years."

How was it dated? Can you explain it? Just curious.

What is a "pretty much" accepted fact? I'm not familiar with this scientific term.

Slarty O'Brian 5 years ago from Canada Author

Can I explain the process? What are you asking exactly?

It is generally accepted now that life was around 3.5 billion years ago. There are always people with alternate views concerning these things. So while it is accepted as fact by main stream science there is always room for doubt and new evidence. Do you have any evidence to the contrary you want to share?

f_hruz 5 years ago from Toronto, Ontario, Canada

Very good hub - thanks for the information! I find it interesting how you point out that DNA and RNA before it may have developed from a more basic information storing system suitable for single cell life forms.

I'd like you to say a few words about your idea of how natural processes maybe able to draw on such ingenious resources in their various stages of development on earth and else where - thanks!

Franto in Toronto

Spirit Whisperer 5 years ago from Isle of Man

If you believe that you are your physical body then the following words you use will fit nicely in your belief system "It amazing to think that what makes us who and what we are comes down to acids, carbon sugars, phosphates, and four bases: thymine, cytosine, guanine, and adenine. That’s what our DNA is made of. The proteins that are manufactured by this code give us our traits and characteristics."

But when I see a loved one lying dead in an open coffin I know that the essence of who that person was no longer resides in the physical body that remains.

The ego says seek and you shall not find has many people searching in vain for answers they cannot find as long as their perception is bound by their belief that they are their bodies.

Thank you Slarty.

Green Lotus 5 years ago from Atlanta, GA

Great Hub Slarty (I'm glad HP is now including Hubs Published on topics we follow in our daily digest).

Fascinating new information (and studies) withing the scientific community are emerging daily. Thanks for reporting about these new theories of DNA and RNA. New discoveries will always be challenged and debated, but then that's how we evolve.

If we stop wondering, studying and testing we'll never find answers..and they will never be "the final answer" :) As they say, there are things you know, things you don't know and things you don't know you don't know. Cheers!

nicomp 5 years ago from Ohio, USA

"It is generally accepted now that life was around 3.5 billion years ago. There are always people with alternate views concerning these things. So while it is accepted as fact by main stream science there is always room for doubt and new evidence. Do you have any evidence to the contrary you want to share?"

Science is not performed by consensus.

Angelladywriter 5 years ago from Media, Pennsylvania

Nice hub Slarty. Your explanation of DNA and how these proteins "manufactured by this code give us our traits and characteristics." Our intellectual ability to discern these issues reminds me of an explanation given by brain surgeon Robert White: "I am left with no choice but to acknowledge the existence of a Superior Intellect, responsible for the design and development of the incredible brain-mind relationship-something far beyond man's capacity to understand." I appreciate this simple explanation.

Our human bodies are "made up with as many as 100 trillion cells." We function daily in life by performing various tasks. How humbling it is when we can say, "How many your works are, O Jehovah! All of them in wisdom you have made."!

Keep writing great hubs.

f_hruz 5 years ago from Toronto, Ontario, Canada

Nature doesn't requite any gods to unfold before your eyes. Only humans, too limited to even communicate with higher forms of intelligence like dolphins or whales, have to have their invisible man in the sky to be happy in their irrational view of reality ... :)

Allana Calhoun 5 years ago from Chicago, Illinois

Fascinating stuff! Nicely written article. Life itself, both philosophically and scientifically is still very mysterious. Not sure if we will ever figure out exactly how, when or where life as we know it started.

Dannytaylor02 4 years ago from United Kingdom, Liverpool

RNA can act like DNA but not anymore? thats not evidence thats speculation on their part to try to fit in with an already flawed theory, but good hub hopefully venter and altman can teach us a lot about life on earth very soon.

and you will probably get flooded with creationists disagreeing with you on this hub just ignore them :)